High-Velocity Stability in Regenesis: Shear-Viscous Adaptation of Vorticity and Emergent Components

Regenesis cosmology posits an eternal barotropic substrate with acoustic horizons, but faces instability at high Lorentz factors (γ ≫ 1) due to vorticity amplification and causality risks. We propose relativistic viscous adaptation: shear viscosity η scales as γ η_nonrel (momentum boost), bulk viscosity ζ thins as ζ_0 / γ (dilution via scattering). This damps runaway effects, traps density gradients as emergent dark matter "ghosts," and yields negative effective pressure for late acceleration—without Lorentz violation. Equations draw from Chapman-Enskog relativistic hydrodynamics. Observational signatures include helical jets (SKA) and scale-dependent cosmic-ray drag.